Photoelectric tube



E. H. BICKLEY PHOTOELECTRIC TUBE Jan. 15, 1946.4

Filed April 16, 1940 2 Sheets-Sheet l Jan. 15, 1946.

E. H. BICKLEY PHOTOELECTRIC TUBE Filed. April 16, 1940 2 Sheets-Sheet 2Patented Jan. 15, 1946 UNITED STATES PATENT ori-ics v PHOTOELECTRIC TUBEEverett H. Bickley, Bala Cynwyd, Pa. Application April 16, 1940, SerialNo. 329,953

(Cl. Z50-165) 18 Claims.

Thepresent invention relates to radiation sensitive devices, and moreparticularly to those known as photoelectric tubes,

Generally, I aim to provide such a device as will be simplified -inconstruction, of more permanent characteristics and longer life, andespecially adaptable for relatively inexpensive, safe and uniformmanufacture by quantity production methods.

A prime object is to provide a novel method and means wherebyapplication of the cathodic light sensitive means at a location forengagement by a coacting contactor is assured.

It is also an object to provide the light sensitive means on theinterior of the envelope of the tube by vaporization and condensation ofa cartridge, andA more specifically through the rise of temperaturenecessary for but prior to the vaporization of the cartridge totemporarily space the contacter therefrom so that the light sensitivemeans will be deposited on the envelope at the zone of contacterengagement when the vaporisation occurs.

Another important object is to provide for establishing conductivitybetween cathodic light sensitive means and contactor selectively at aplurality of zones or locations, which especially enables expeditiouscorrection of an inoperative, partially impaired or faulty conditionattributable to faulty deposition, displacement or wear of the lightsensitive means.

I further aim to provide a tube especially having great stability, speedand high response to the radiations in the spectral region commonlycalled blue and of shorter wave length.

I also aim to provide a novel form and composition of vaporizablecartridge used in the formation of the light sensitive electrode coatingwithin the envelope or tube.

Various additional objects and advantages will become apparent from aconsideration of the description following, taken in connection withvthe accompanying drawings, illustrating operative exemplaryembodiments.

In said drawings:

Figure 1 is a central longitudinal sectional view through aphotoelectric tube constructed in accordance with the invention;

Figure 2 is a cross sectional view taken on the plane of line 2-2 ofFigure 1;

Figure 3 is a central longitudinal sectional view through thephotoelectric tube of Figure 1 in the course of manufacture thereof,taken at right angles to Figure 1;

Figure 4 is a cross sectional view taken on the Figure 9 is alongitudinal sectional view through another modiiied form ofphotoelectric tube; and. Figure l0 is a longitudinal sectional viewthrough a further modied form of photoelectric tube.

Referring specifically to the drawings, and rst, to the form of Figures1 to 5, I0 designates a suitably shaped bulbous evacuated envelopeadapted to be mounted on a conventional base, or other--V wise, as usualin the art. Said envelope may be of lime glass, fused quartz, or othernon-conducting material which is not chemically detrimental to thematerials or parts it encloses.

Said envelope has an inturned press Il at one end thereof containingspaced apart short conductor wires l2 and I3 which are sealed in and bythe glass when the latter is blown to provide the press and to the outerends of which wires l2 and I3, exterior conductor leads i4 are welded.At the time the envelope with the press Il` is blown, an integral glasstube i5 (Figure 3) is attched through which the envelope is later evacuaed.

Welded to the inner end of said wire l2 is an electron collectingelectrode i6 which is relatively.

rigid and unbendable by heat. A contacter Il is thermostatic so as to bebendable by heat to move both inwardly and sidewise away from its normaloperative position engaging the inner wall of the envelope, as shown infull lines in Figures l and 3, toward electrode I6 to the dotted linepositions in the same gures. Usually, contactor l'l is bimetallic and iswelded to a connectingconductor |B, which, in turn, is welded to the.

inner end of the adjacent conductor wire i3. For the electrode i6 andconnector i6, I preferably employ a metal having Ya thermal coecient ofexpansion relatively high with respect to that of the material of pressIl, so that on cooling, the metal will shrink away from the glass of thepress leaving a space between such glass and the electrode I6 andconductor I8.

When the electrode iis secured in place, it carries a cartridge I9welded or otherwise secured thereto at connection 20, andalso carries asmall nickel, steel, tantalum or other metallic washer or disk 2l weldedto the electrode I6 and normally spaced'about d: of an inch fromthepl'eSS.

Said cartridge I9 generally corresponds to and4 23 during the marginalwelding Vthereof togetherV at 24. The pellet 26 is preferably composedof 1.26 parts of dehydrated potassium chromate and 1.00 part of a finemetallic powder prepared from barium and aluminum alloy combined in theproportion of 1 part barium-'toV 1 part aluminum, all parts mentionedand to bermentioned beine` by weight. If desired, from approximately0.15 part to approximately 0.25 part, by weight, of finely powderedmagnesium may be `added. Where the pellet is too soft, aluminum powdercan be used as a binder. I may substitute as the ne metallic powder,with 1.26 parts of highly compressed potassium chromate, 1 part ofpowdered magnesium and aluminum, combined in the proportion of 1 partmagnesium to 1 part of aluminum. The proportions may be varied sincepellets have been produced having 5 parts of potassium bichromate orpotassium .chromate down to 1/2 part of either potassium blchromate or`potassium chromate to l' part of the fine metallic powder. The potassiumchromate is preferred over potassium bichromate because less gas isevolved and the pellets can be made smaller, since a large quantity ofthe potassium bichromate hasrto be used in proportion to the metallicpowder to obtain the same yield of potassium.

The envelope I6 is usually transparent and provided at any desiredlocation with a window Ia for the reception of the desired radiations bythe tube. v 1 f The parts are all assembled as described before theenvelope I0 is evacuated and before vaporization of the pellet 26 incartridge I9, the tube at such stage being as shown in Figures 3 and 4.The gases'and vapors are evacuated from the envelope IIJ in any knownmanner through the tube I5, following which the tube is thoroughlyYbaked at high temperature and the metal .parts are heated byelectro-induction Vor other means until all absorbed and adsorbed gasesand vapors are driven o. Thereafter, the cartridge I9 is subjected toadditional heating of a higher degree, sufllcient to decompose thepellet and release the vapors therefrom through ports26' which vaporscondense on and adhere to the inner surface of the envelope which isrelatively cool to form the light sensitive cathode nlm 21. Afteradditional evacuation to a high point, the tube I is sealed oil with atorch.V Before sealing off, asmall amount of inert gas such as argonmayV bea-introduced or hydrogen sensitization may be used according toknown methods. Electrode I6 constitutes an anode coacting with thecathode 21, and they are insulated from each other 'by the glass of theenvelope at the press.

Attention is particularly called to the fact that upon subjecting thedevice to heat-the contactor I1 will be heated and will move inwardlyand.

sidewise from the fullline position shown in Figure 1 to the dotted lineposition in the same ligure, thereby exposing that portion or zone ofthe inner surface of the envelope I0 which it normally engages, and,hence, during vaporization, the vapor from the cartridge will enter suchzone andrdeposit and condense thereat, the contactor I1 upon coolingautomatically moving to its original or normal position and engaging thefilm 21 at such zone. It is also to be noted that whenV the cartridge I9is heated, the disk 2| also becomes heated, and during the vaporizationof the pellet 26, the disk 2I prevents condensation of conductivematerial thereunder. 1n a vacuum, vapors move in straight lines fromtheir source until condensed. They are reiiected from any heated objectand for that reason the contactor I1 is moved sidewise and away so thatno shadow will be formed on the envelope where it normally rests when atroom temperature. Should the vapor condense on the press and shortcircuit the elements I6 and I8, when the tube is in use, induced radiofrequency eddyv currents may be used to heat the washer'ZI, thus drivingaway the condensation and eliminating leakage.

Various changes may be resorted Ato provided they fall within vthespirit vand scope of the invention. For instance, `I may use themodified form of Figure 6. This form corresponds to that just described,except as follows: The contactor I1 corresponds to that at I1 and likethe former, is'thermostatic, being of one kind of Vmetal or bimetallic,as preferred. Surrounding the contactor I1( at the neckor collar 28(Figures "l and 8) is a metallic contact 29. This contact 29 may beofany suitable shape and, forin-l stance, capable of .beingmanufacturedbyqstamping. As shown,1it `is triangular in form.

As the photoelectric tube of yFigure 6 is manu; factured, the distal endportion of the contacter I1' isvin engagement with the electrode 21,- asin Figure 1, and thecontact 29 is out of engagement with such electrode21, being in a retracted position, shown by dotted linesin Figure 6. l

Should engagement or contact between -the electrode 21 and contacter 11'be faulty at the time oi'manufacture orl become faulty in use from wearVor forV various reasons, effective contact may be reestablished bydisposing the photo. electric tube of Figure 6 in an Yinverted positionlwhereby the contact 29 is uppermost, thereupon subjecting thephotoelectric tube to a jolt Awhich causes the contact 29 to slidefromthedotted line position of Figure 6 to the full line Vpositio'nofthe same figure. Attentionis called to the tact that the contact 29 isso proportioned that a part thereofV wedges; between electrode ,-2-1Vand; the

contactor VI1 so'thatthe latter Vis under tensign when the contact 29 isin the position of Figlllfei and, hence, leiective engagement of -theYlatter with the electrode ,21 is maintained. Also note that, as bestshown in Figure 7,' the contact-,2,9 at a plurality of yspacedlocations-30, is in en-v gagement with electrode 2 1 to insure effectiveengagement. This contact 29 isrheld inthe Vfull line position of Figure6 by the frictional tension of contacter I1', in addition tocohesionbef. tween the contact 29 and electrode 21.

The distal end of the contacter I1' maybe curled or otherwise enlargedat 3| to prevent dis engagement of thecontact 29 therefrom Since thecontact29 engageslelectrode 21 at spaced locations, which are'onopposite. sides-,of and out of the zone of engagementof contacter. II`with electrode 21 l15h12 photoelectrictube may be manufactured .with thecontactor .11 `Without thermostatic .properties :because afterdeposition ofthe electrode 2l, 'the contact 29 couldbe lolted from the,dotted -line position of Figure 6 to `.the

full-line iposition thereof, and retained in place through thefrietional tension `of the contacter I1 and engaged at the two locations30 with electrodell.

The form of Figure 9 corresponds :to that-of Figure .6, with theexception of the contactor shown at Il", which corresponds .to thoseshown at ITI .and i1. This contactor I1," maybe made of one kind ofmetal or bimetallic, as preferred, but usually has afmetal wire of asingle kind of metal and .normally ,of arcuate :.shape, `as shown. Thecontact 29 is also employed, .being mounted on Vthe contactor 1H" tofunction 'in lthes'ame marmer as in Figure 6.

i The contact 29 `is of a metal which may be attracted by a horseshoemagnet and, hence, by moving the magnet along the outside of .theenvelope, the contact 29 may be moved from `the dotted line position inFigure 6 to the full line position shown in Figures 6 and 9, thehorseshoe magnet being fragmentarily suggestedin the latter figure.

In Figure 10, a mica, metallic orother extension .33 is attached `to an`electrode i6 .corresponding to that at i6, and a contactar Ila isemployed in lieu of those .at Il, Il' and l1". This contacter Ila isresilient, being a wire, of .a single kind of metal or bimetallic, aspreferred. This contacter Ila has an angular extension 34 provided witha hook at 35 adapted for detachable engagement with the distal end ofextension 33, as shown in dotted lines in Figure 10, whereby thecontactor lla throughout is spaced from the electrode 21. The contactorI la is in such dotted line position when assembled in the photoelectrictube and the latter is evacuated and the cartridge I9 vaporized,Following deposit of electrode 21 through such vaporization, thephotoelectric tube may be inverted, causing the contact 29 to slide intothe solid position shown and then the tube is jarred or jolted to eiiectthe disengagement from hook 35 through extension 33, so that theresilience of contacter Ila or the contact 29 Will engage the electrode21.

Attention is called to the fact that the terms contactor and contactormeans as used in the claims are of a breadth to include not only anelement like Il, Il', Il" or Ila, but also an element Il, l1', I1" orlla, or any equivalent,

plus the element or contact 29, or any equivalent,v

as a part thereof.

I claim as my invention:

l. A photoelectric tube having an envelope, contactable light-sensitivemeans therein, an electrode to coact with said means, a contactor means,said electrode and contactor means being mounted and sealed within saidenvelope, said contactor means being normally in engagement with saidlight-sensitive means and movable by inertia into and out of engagementwith said light-sensitive means.

2. A photoelectric tube comprising an envelope having an electrode and acontactor therein, a photo-electric surface within said envelopenormally engaged by said contactor, vaporizable means Within theenvelope to provide a lightsensitive deposit on said surface to coactwith said electrode, said contacter being movable by heat of a degreeinsuilicient to vaporize said means to expose said surface beforevaporizing said means to enable deposition at the zone of engagementface.

i :3. A iphotoelectric itube having an=envelope,1a light-*sensitive:electrode `means therein, an electrode tocoact Withsaid electrodemeans, acontactor engageable with said electrode means, and a .contact:carried by :the .contacter and movable along .the same toengage said.electrode means.

4. '1A `.photoelectric tube according to claim 3 wherein. said contact:is `sized and proportioned to .wedge at .a part `.thereof .between theelectrode means and :said fcontactor to :tension the latter to :maintainthe `contact -in `the wedged position.

:5. A -photoelectric tube having anenvelope, a photoeelectric Vcathodetherein, an electrode therein coacting with said cathode, a conductingsupport'iwithinithe .envelpa Tand a conductive contact variable as toposition relative `to the support :and .cathode held against lsaidcathode by:said:support.

6. A. photoelectric .tube having van envelope, la light-sensitivecathode therein, electrode `means andacoutactor extending into theenvelope,.said contacter `being tensioned :to normally engagesaidcathode, and Aa separable connection between .the vcontactor andelectrode means to hold the contactor-out .of contact with the envelopeat the zone of normal engagement, said connection being:separable-.through jolting `of the envelope.

7. .A material to be vaporized within envelope of a photoelectric .tubevto'provide .a cathode, 'the `n iateri'al comprising .by weight, 1.23parts of :potassium chromate and `-1.00 part of a ilne metallic powderof a barium and aluminum alloy combined in the proportion of 1 partbarium and 1 part aluminum.

8. A material to be vaporized within an envelope of a photoelectric tubeto provide a cathode, the material comprising by weight, 1/2 to 5 partsof either of the group of potassium chromate or potassium bichromate.and 1 part of iine metallic powder of barium and aluminum mixedtogether.

9. A material to be vaporized within an envelope of a photoelectric tubeto provide a cathode, the material comprising by weight, 1.26 parts ofpotassium chromate and 1.00 part of a fine metallic powder of a bariumand aluminum alloy and combined in the proportion of 1 part barium and 1part aluminum and from approximately 0.15 to 0.25 part of magnesium.

10. A material to be vaporized within an envelope of a photoelectrictube to provide a. cathode, the material comprising by Weight, 1.26parts of potassium chromate and 1.00 part of a ne metallic powder of a.barium and aluminum alloy combined in the proportion of 1 part bariumand 1 part aluminum and aluminum powder as a binder.

1l. A photoelectric tube having an envelope with a photo-sensitivecathode coating therein, an anode adjacent thereto, a movable contactormeans, said anode and contactor means being mounted within saidenvelope, said contactor means being normally in engagement with saidcoating and movable into engagement with said coating at a plurality ofzones of the latter.

12. A photoelectric tube having an envelope, a cathode therein, aconducting support within the envelope, a contact positioned by thesupport in engagement with the cathode, said contact being movablerelative to the support through joltlng of the latter to differentpoints of engagement with the cathode.

13. A material to be vaporized within the en of zthe electrode `with:the said fsur` Y process comprising heating said contactortodisplacethe contacting portion thereof from.- said envelope, andVcoating therinner surface of said envelope with a photo-sensitivematerial torform Va; photofsensitive cathode including the area..nor.

mally engagedby saidpcontactor. i, t u A n .15; The process ofmanufacturing a photoelec.- tric tube having ancenvelope enclosing ananode, there being-lead-in means for afphoto-sensitive electrodecomprising a bimetalliccontactor, said process comprising heating saidcontactor to displace the 4contacting portion .thereof fromA saidenvelope, and coating the inner surface. of said envelope throughsubjection of the photo-sensitivematerial to heat of a temperaturehigher than during `the aforesaid heating to forni a photo-sensitivecathode including the area normally engaged by said contactor. Y

16. The process of manufacturing a photoelectric tube having an envelopeenclosing an anode, there beingl leadfin means for a photo-sensitiveelectrode comprising a bimetallic contactor and a contactmovably mountedthereon, said .process aanmaacomprising heating said contacto'r todisplace the contacting portion thereof from said envelope, and Ycoatingthe inner surface of said envelope with a photofsensitivematerial toform a photo-` tric tubehaving an envelope enclosing an anode,Y

there A'being lead-in means for a photo-sensitive electrode comprising abimetallic contactor and a.

contact moi/ably vmounted thereon, said process comprisingheating saidcontactor to displace the contacting -portion thereof from saidenvelope,

and coatingv the inner surface of said envelope with a photo-sensitivematerial to form a photosensitive vcathode including Ythe areav normallyengaged by said contactor, and magnetically moving said contacton thecontactor to position, the contact relatively to the photo-sensitivecathode. A

V18. A capsule for vaporizationto provdea cathode vapor comprisinginitially separate disks having opposed depressions, a vaporizablecompressed pellet Within and of a size filling and intimately iittingthe depressions to cause registry of the disks in manufacturing thecapsule, the walls of the depressions having dischargeports, and meansmarginally securing the disks together against rupture during dischargethrough the said ports. t Y

EVERETT H. BICKLEY.

